KR0172943B1 - Receiver for tv and teletext signals including a teletext decoder and an adaptive waiting time reduction circuit - Google Patents

Abstract

By using a television receiver or video recorder having a multipage teletext decoder and a nonvolatile page number memory, a teletext page having a page number stored in the page number memory can be accessed without waiting time.

In order to facilitate the operation, the numbers of frequently referenced pages do not need to be programmed by the user, and are automatically stored in the page number memory according to the usage pattern. The number of each requested page for this purpose is stored in the page number memory 12, and if the oldest page number or the entered number has already been stored, this same page number is removed from the memory. Thus, the page number memory always contains the most recently requested page numbers.

Description

Television and Teletext Signal Receivers

1 diagrammatically shows the configuration of a television receiver having a multipage teletext decoder.

2A and 2B show two possible combination forms of page number memory for storing N page numbers and priority assigned to page numbers.

3 to 7 are diagrams for explaining the operation of the television receiver shown in FIG.

* Explanation of symbols for main parts of the drawings

1: antenna 2: tuning and demodulation circuit

3: video signal processing circuit 4: multipage teletext decoder

4.1: Clipping Circuit 4.2: Acquisition Circuit

4.3: page memory 4.4: display circuit

5: switch 6: display screen

7: command bus 8: control circuit

9 (remote) control unit 10: receiver circuit

11: interface 12: storage medium, page number memory

[Field of Invention]

The present invention relates to a television and teletext signal receiver comprising a teletext decoder capable of retrieving a plurality of teletext pages and storing them in the page memory. The receiver also includes a page memory in which a predetermined teletext page number is appropriately stored when the receiver is switched off. Such a receiver may for example be a television receiver or a video recorder.

[Prior art]

Television receivers or video recorders, including teletext decoders, typically have a (remote) control system that allows the user to switch on the teletext operating state and generate the desired page number with the aid of the numbered keys. By doing so, you can search pages one after another. The command given by the user is applied to the control circuit, where the command is decoded and sent to teletext decode. In particular, a page having a designated page number can be retrieved by the decoder, stored in the page memory and displayed on the display screen. Teletext pages are sent periodically, which lasts for an appropriate period of time, so it takes some time for the desired page to appear on the display screen.

This waiting time can be significantly reduced by taking some action. For example, Ref. [1] suggests storing periodically transmitted pages in a memory in the order of reception. After a page is requested by the user, the decoder retrieves the page's presence in page memory. Since the page memory must include at least the required number of periodically transmitted teletext pages, the waiting time can be significantly reduced, so a large memory is needed for this purpose. However, such large memory is relatively expensive.

In order to solve the above problem, a teletext decoder has been developed which has a limited but appropriate number of pages to be retrieved and stored, and has a register specifying the page number to be retrieved. One example of such a decoder is described in Ref. [2]. In this type of teletext decoder, hereinafter referred to as a multipage Peletext decoder, latency reduction is achieved by filling the registers to match the page to be actually displayed as much as possible. For this purpose, it is proposed in Ref. [3] to store a series of page numbers specified by the user in the page number memory and to display these pages continuously later. Such a television receiver is particularly good when the number of pages that the multipage teletext decoder can store is relatively small, for example less than the number of stored page numbers.

In fact, the latency is effectively reduced because the multipage teletext decoder retrieves, for example, the first four pages of pages that are deemed to be displayed. It is preferable to use a nonvolatile page number memory to ensure that the stored page numbers are preserved even after the receiver is switched off.

The drawback of the receiver is that the user must clearly store the number of the page to be displayed in the page number memory. This means that the user intentionally puts the numbers in the desired sequence and, for example, must issue a specific control command that terminates the page number using a memory key. The receiver also has the drawback that once the page number memory becomes full, no further page numbers can be entered thereafter. In addition, since the pages are displayed in the order in which they are stored, in order to display a desired desired page, a large number of pages irrelevant at that moment cannot be passed by the operation of the recall key. Thus, the ease of operation of the known receiver is in fact a drawback.

[OBJECTIVE AND SUMMARY OF THE INVENTION]

The object of the present invention is to further facilitate the operation of the receiver for television and teletext signals, in particular including a multipage teletext decoder and page number memory, and to significantly reduce the waiting time.

According to the present invention, in order to achieve the above object, a priority is assigned to a page number in a page number memory, which priority is related to the order in which the page number is generated by the operating system. In particular, the control circuitry is adapted to refresh the priority of the page number generated by the operating system when the page number is stored, and to remove the oldest priority page number from the page number memory when the memory is full. have.

By doing this, the page number memory is stored in nonvolatile page number memory, taking into account that the user frequently requests the same page frequently during normal use so that the page number memory always contains the most recently requested page number. It is good to keep it. The page number inserted by the user is implicitly stored in the page number memory. In other words, the user does not need to activate additional memory keys. The page corresponding to the stored number is retrieved directly by the multipage teletext decoder and can be displayed immediately if desired. Thus, the relevant page can be accessed without waiting, and the user does not need to activate additional recall keys. If the usage pattern changes over time, that is, if the requested page number changes, they are automatically stored, and after some time the page numbers that are no longer requested eventually disappear from memory. Therefore, such a receiver is suitable for the usage pattern.

In another embodiment according to the present invention, in response to the generation of the page number already stored, the same page number stored in place of the page number having the oldest priority is removed from the page number memory. Also, in response to the occurrence of the page number already stored, control to adjust the priority of other page numbers in the page number memory by assigning the most recent priority to the relevant page number already stored without storing the page number. It is also possible to modify the circuit.

In this way, since only different page numbers are stored, the page number memory can be used more efficiently. Therefore, it should be noted that the priority of the stored page numbers does not necessarily fully indicate the order of generating page numbers. For example, a page number removed in the middle may have been initially stored between two page numbers with consecutive priorities.

If the generated page number has not yet been stored in the page number memory, it is advantageous to prohibit the storage of the generated page number as long as the page corresponding to the page number is not displayed on the screen for a predetermined time. This prevents incorrectly entered page numbers and numbers of pages not being transferred.

If desired, the receiver may be equipped with a special recall key in accordance with the method described in Ref. [3] to continuously display the appropriate page stored without waiting time.

[references]

[1] Teletext device with reduced page access time. European Patent Application No. 0,118,950.

[2] teletext signal processing circuit for a teletext receiver. European Patent Application No. 0,220,763.

[3] A television receiver having a teletext decoding circuit and a page number memory. United States Patent No. 4,701,794.

[Description of Example]

One embodiment of a television receiver is shown diagrammatically in FIG. The transmission signal received via the antenna 1 is applied to a conventional tuning and demodulation circuit 2. The composite video signal CVBS of the selected television program is applied on the one hand to the conventional video signal processing circuit 3 and on the other hand to the multipage teletext decoder 4. In the normal operation state of the receiver, the basic color signal R 'G' B 'generated by the video processing circuit 3 is applied to the display screen 6 via the switch 5 so that the user receives the received television program. In the teletext operation state, which enables viewing, and which can be called by the user, the basic color signal RGB of the multipage teletext decoder 4 is displayed on the display screen 6 via the speech 5.

The multipage teretext decoder 4 includes a clipping circuit 4, 1 for reproducing a digital teletext data signal TDT and an associated clock signal TTC from an applied video signal CVBS, and a plurality of selected pages. Acquisition circuits 4 and 2 for automatically capturing, page memories 4 and 3 in which the acquired pages are stored, and display circuits 4 and 4 for converting selected and stored pages into basic color signals RGB. ). The display circuits 4 and 4 also generate a blanking signal BLK, by which the switch 5 is activated and the display of a normal television program is blanked in the teletext operating state.

The multipage teletext decoder 4 is connected to the control circuit 8 by a command bus 7. The multipage teletext decoder receives, via the command bus of the control circuitry, not only the number of pages to be displayed but also the number of pages that are captured and stored in particular.

The operation command given by the user is generated in the (remote) control unit 9 and applied to the control circuit 8 via the receiver circuit 10. As soon as the user selects the teletext operation state, the multipage teletext decoder 4 receives a command from the control circuit 8 via the command bus 7 to display the color signal RGB of the teletext page to be displayed. The blanking signal BLK is activated to be applied to (6).

An interface 11 for tuning the control circuit 8 to the transmitting station to control brightness, volume, etc. is also connected to the command bus 7. These are marked with appropriate symbols in the figures. In addition, a nonvolatile storage medium 12 is preferably connected to the command bus 7 to control all kinds of data that should not be lost when the receiver is switched off, such as tuning data, picture and sound adjustments, and the like. (8) can remember. In particular, part of the memory is used to store multiple teletext page numbers. The storage medium section 12 is referred to as a page number memory below.

When the page number is stored in the page number memory 12 using the control circuit 8, a priority relating to the order in which the page numbers are generated is assigned to the stored page numbers. Two possible forms of memory organization for this purpose are shown in Figures 2a and 2b. FIG. 2A shows a schedule table in which page numbers are stored in random memory addresses, where numbers indicating priorities are explicitly added to each page number. The page number with priority 1 is the most recently generated, i.e., the most recent page number, and the page number with priority N is the number that has been stored for the longest period, that is, the oldest number. 2B shows a series of N registers R (1) through R (N) each having a page number, where register R (1) contains the most recently stored page number and register R (N)) includes the oldest number, so the priority of the page numbers is determined internally according to the position of the page number in the page number memory 12 in the organization table, for example, the page number having priority 4 Should be given a new rank 5, then priority 4 is replaced by priority 5 in the associated memory address in the programming table according to FIG. 2a, whereas in the programming table according to FIG. 2b the page number of the register R (4) is registered. If it is shifted to (R (5)), the two tables are equivalent, hereinafter the table according to FIG. 2b is used.

The operation of the receiver shown in FIG. 1 is determined by the control program stored in the control circuit 8, which is suitably realized in the form of a microprocessor. After the receiver is switched on or after a different television program is tuned, the control program proceeds first through the following steps in a known manner. That is, the page number and page number 100 stored in the registers R (1) to R (N) of the page number memory 12 are transferred to the acquisition circuits 4 and 2 via the command bus 7. The circuit then captures the relevant teletext page in an automatic manner and stores it in the page memory 4, 3. Therefore, it is estimated that the multipage teletext decoder can receive and store at least one or more pages than the number of page numbers stored in the page number memory 12. Page 100 is typically called because it contains the primary index and becomes the first page displayed on the display screen in teletext state. Using this portion of the control program, when the user selects the teletext state, the pages with the page numbers stored in the page 100 and the registers R (1) to R (N) are already found and stored.

Another control program in the teletext state is shown in FIG. In step 13 the control program checks if the user has entered a page number. If no entry has been made, the program returns to step 13 and continues to wait for entry of the page number. If a page number has been entered, in step 14 the multipage teletext decoder is commanded in a known manner to obtain the page with the entered number, to store it and display it on the screen. This often happens that the requested page, i.e., the page with the number entered, is not yet memorized and will not be executed immediately, so the user has to wait until the page is sent by the transmitter. However, if the entered number was already stored in the page number memory, the requested page would have already been found and stored. In this case, the requested page is displayed immediately.

While the multipage teletext decoder automatically executes the command obtained in step 14, the control program proceeds to step 15, where the priority assigned to the stored page number is in register R (1). The contents of the register R (2) are adjusted by putting the contents into the register R (2) and the contents of the register R (2) into the register R3. The original contents of the register R (N) are then removed. In step 15, the register R (1) emptied is filled with the page number input in step 16, so that the most recent priority is assigned to the page number. The modified contents of the page number memory are delivered by a method known to the multipage teletext decoder via a command bus to obtain a designated page in the page number memory. It not returns to step 13 goes to wait for a request.

4 shows by way of example what happens in the contents of the page number memory 12 when executing the control program of FIG. 3, in which case the page number memory stores 10 page numbers. . The situation before the page number is entered by the user is shown on the left and the situation after the page 101 is requested is shown on the right. It is assumed that page 101 already exists in memory, in this case in register R (7), so that the page is displayed on the screen without waiting after the request.

As can be seen from the foregoing, the original page number stored in R (1) is shifted by one digit in the page number memory each time a new page is requested, and eventually disappears from the memory after N times. Therefore, the page number memory always contains the number of the N most recently requested teletext pages, where R (1) contains the most recently requested page on the screen and R (N) contains the oldest page. Include. If a user refers to a page with a number already stored, the number of the page is not lost since it is written back to register R (1) before disappearing from register R (N). Thus, the user can obtain the page on the display screen immediately after entering the page number without waiting time. However, if, for example, the user becomes interested in different topics of pages with different numbers and the usage pattern changes, the new number is stored in the page number memory and the old number automatically disappears after some time. The receiver thus provides a suitable latency reduction, which is very good for teletext references.

As a result of the control program of FIG. 3, the page number is often stored in the page number memory more than once. In fact, if a page with a page number already stored is requested, the priority of the stored page number is increased but the page number itself is not removed from memory unless it is the oldest page number. This significantly reduces the possibility of storing as many different page numbers as possible in the page number memory. By using the control program as shown in FIG. 5, the page number memory can be used more effectively. The control program differs only in that step 15 is replaced with steps 18 to 20 from that shown in FIG.

In step 18, the auxiliary index n is given an initial value of 1. The page number memory 12 then executes from R (1) in step 19 to check whether the stored page number is the same as the input number. If it is the same, step 19 is terminated and R (n) contains the same page number. If the entered page number is not found in any register, step 19 is terminated because the auxiliary index n reaches the maximum value N. Subsequently, step 20 is executed. This step is substantially the same as step 15 described above, and is used to advance the page number to the subsequent register of the page number memory. However, only the page numbers in registers R (1) to R (n-1) advance one position and the numbers in R (n + 1) to R (N) are not affected. Since the register R (n) contains a page number corresponding to the input page number, the original contents of the register R (n) are removed as intended. The page number input in step 16 is stored in the register R (1) as the most recent page number. Thus, the page number memory now contains only different page numbers.

6 shows an example of the contents of the page number memory 12 before and after storing a new number in the above embodiment of the control program. The page number stored in the original register R (7) corresponds to the entered number and therefore for this reason the number is removed from the page number memory. The relevant page number 101 is now stored in register R (1) as only the most recent number. The page number 210 stored in the register R (10) is preserved so that the page 210 remains accessible without waiting time.

When referring to teletext, it happens regularly that the requested page was not sent. The incorrectly entered number for the page number is corrected by perfecting the wrong page number by immediately entering the desired number. After looking through the display, you may find that the expected content is not present on the displayed page. In all such cases, the page number is entered without preceding the display of the desired page on the display screen. Therefore, it is unnecessary to store the page number in the page number memory. As shown in Fig. 7, the control program has a step 21 for this purpose, in which it checks according to a known method whether a page corresponding to the input page number is actually captured and displayed. If not, it is possible to insert a new page number via step 13.

If a page with the entered page number is found, it is checked in step 22 by a known method whether a certain time has elapsed after the page reception. If the page with the entered page number has been displayed for a predetermined time, the priority of the page numbers is adjusted according to the method described above at steps 18, 19 and 20, and the entered number is stored at step 16 and the adjustment is made. The page number is then applied to the multipage teletext decoder for further acquisition in step 17. Note that for the sake of completeness at least the adjusted time interval during page display may be zero.

Claims (9)

An operating system for generating a page number of the teletext page desired by the user, a first input for receiving the teletext signal, a second input for receiving the page number of the teletext page, and an image signal output A teletext decoder for retrieving and storing a teletext page corresponding to the received page number, a page number memory for storing at least two page numbers, the page number memory, the operating system, and the teletext decoder Coupled to apply to the teletext decode a page number stored in the page number memory and a page number generated by the operating system, and select to display a teletext page with the page number generated by the operating system Doing A television having a control circuit for storing page numbers generated by a pre-operating system in the page number memory, and a display screen coupled to the image signal output of the teletext decoder for displaying a teletext page selected for display; A teletext signal receiver, wherein a priority is assigned to a page number in the page number memory, the priority being related to the order in which an operating system generates the page number. 2. The apparatus according to claim 1, wherein the control circuit assigns the most recent priority to the page number when the page number generated by the operating system is stored in the page number memory, and the other page number in the page number memory. Television and teletext signal receiver, characterized in that it also adjusts the priority of. 3. The television and the telecom of claim 2, wherein the control circuit removes a page number having an older priority from the page number memory when the page number generated by the operating system is stored in the memory. Text signal receiver. 4. The television and teletext signal receiver of claim 3, wherein if the page number memory is full, the page number to be removed is the page number with the oldest priority. 4. The television and teletext signal receiver according to claim 3, wherein the page number to be removed is the same page number as the page number stored in the page number memory. 2. The control circuit according to claim 1, wherein, in response to the occurrence of the same page number as the page number stored in the page number memory, the control circuit prohibits the storage of the generated page number and is most recent to the associated page number already stored. And assigning a priority and suitably adjusting the priority of other page numbers in the page number memory. 7. In response to the occurrence of a page number not yet stored in the page number memory, the control circuitry causes the teletext page corresponding to the page number to be displayed on the screen for a predetermined time period. Television or teletext signal receiver characterized in that the storage of the generated page number is prohibited unless otherwise indicated. The television set according to any one of claims 1 to 6, wherein the operating system generates an operation command for continuously displaying pages corresponding to the page number stored in the page number memory on a display screen. Teletext Signal Receiver. 8. The television and teletext signal receiver of claim 7, wherein the operating system generates an operation command for continuously displaying pages corresponding to the page number stored in the page number memory on the display screen.

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